The man given much of the credit for overseeing the development of Microsoft's Word software blasted into space over the weekend as the fifth space tourist.

Charles Simonyi, who was once chief architect at Microsoft and now runs his own development company called Intentional Software, began his journey into space from the Baikonur Cosmodrome in Kazakhstan at just after 11:30 p.m. Saturday local time. Simonyi traveled with Russian cosmonauts Oleg Kotov and Fyodor Yurchikhin inside the Soyuz TMA10 spacecraft.

The three are due to dock with the International Space Station later Monday. Simonyi, who had to undergo six months of training for the flight, will spend more than a week on the space station before his scheduled return to earth on April 20.

The flight, which sees Simonyi occupy a seat that would otherwise have been vacant, was organized through Virginia-based Space Adventures. It cost Simonyi about US$20 million.

While on board, he will do some research work on behalf of the Hungarian Space Office, measuring the amount of radiation that he is exposed to onboard the ISS.

Simonyi has been keeping a blog during the buildup to launch and in his last entry, posted on Saturday morning, he wrote, "I'm really looking forward to the flight."

In addition to his work at Microsoft, Simonyi invented Bravo, the first WYSIWYG editor, at Xerox's Palo Alto Research Center.